ESTUDO TEÓRICO E EXPERIMENTAL DA DESPOLIMERIZAÇÃO DE POLIURETANOS: UMA NOVA VISÃO PARA RECICLAGEM QUÍMICA

A crescente demanda por materiais poliméricos em vários setores industriais e até mesmo na vida cotidiana, tem como consequência um grande volume de resíduos gerados. Os métodos de reciclagem química são uma opção para reduzir o impacto causados pelo descarte inadequado desses materiais. O estudo de parâmetros cinéticos e termodinâmicos das reações de despolimerização podem ajudar a otimizar processos existentes bem como auxiliar no desenvolvimento e estudo de viabilidade de novos processos. Outra ferramenta com grande potencial para estudos de processos de reciclagem química é a modelagem molecular. Através de cálculos computacionais é possível identificar previamente quais os produtos gerados em uma reação química, o mecanismo de reação para o processo além de determinar os parâmetros cinéticos e termodinâmicos. No presente trabalho, é proposto uma nova metodologia para a despolimerização do poliuretano. Para esse processo foi determinado o mecanismo de reação e efetuado estudo cinético e termodinâmico utilizando ferramentas de modelagem molecular. Os dados experimentais obtidos no processo de despolimerização do Poliuretano pós consumo (PU) foram comparados com dados teóricos sendo possível mostrar uma boa correlação entre os valores de energia de ativação (93,37 kJ˖mol-1 obtido experimentalmente e 96,51 kJ˖mol-1 através de cálculos teóricos) e entalpia de ativação (experimental de 89,77 kJ˖mol-1 e teórico 93,19 kJ˖mol-1).Além disso, através de cálculos semi-empíricos, foi estimado com precisão os produtos de reação além de determinado o mecanismo no qual a reação ocorre

Mapping specificity, cleavage entropy, allosteric changes and substrates of blood proteases in a high-throughput screen

Proteases are among the largest protein families and critical regulators of biochemical processes like apoptosis and blood coagulation. Knowledge of proteases has been expanded by the development of proteomic approaches, however, technology for multiplexed screening of proteases within native environments is currently lacking behind. Here we introduce a simple method to profile protease activity based on isolation of protease products from native lysates using a 96FASP filter, their analysis in a mass spectrometer and a custom data analysis pipeline. The method is significantly faster, cheaper, technically less demanding, easy to multiplex and produces accurate protease fingerprints. Using the blood cascade proteases as a case study, we obtain protease substrate profiles that can be used to map specificity, cleavage entropy and allosteric effects and to design protease probes. The data further show that protease substrate predictions enable the selection of potential physiological substrates for targeted validation in biochemical assays

Patterns of novel alleles and genotype/phenotype correlations resulting from the analysis of 108 previously undetected mutations in patients affected by neurofibromatosis type I

Neurofibromatosis type I, a genetic disorder due to mutations in the NF1 gene, is characterized by a high mutation rate (about 50% of the cases are de novo) but, with the exception of whole gene deletions associated with a more severe phenotype, no specific hotspots and few solid genotype/phenotype correlations. After retrospectively re-evaluating all NF1 gene variants found in the diagnostic activity, we studied 108 patients affected by neurofibromatosis type I who harbored mutations that had not been previously reported in the international databases, with the aim of analyzing their type and distribution along the gene and of correlating them with the phenotypic features of the affected patients. Out of the 108 previously unreported variants, 14 were inherited by one of the affected parents and 94 were de novo. Twenty-nine (26.9%) mutations were of uncertain significance, whereas 79 (73.2%) were predicted as pathogenic or probably pathogenic. No differential distribution in the exons or in the protein domains was observed and no statistically significant genotype/phenotype correlation was found, confirming previous evidences

Prognostic significance of germline BRCA mutations in patients with HER2-POSITIVE breast cancer.

Background: HER2-positive breast cancers are rare amongst BRCA mutation carriers. No data exist regarding clinicopathological characteristics and prognosis of this subgroup of patients. Materials and methods: Using a retrospective matched cohort design, we collected data from 700 women who were diagnosed with operable invasive breast cancer from January 2006 to December 2016 and were screened for germline BRCA mutations. Clinicopathological features and survival rates were analyzed by BRCA and HER2 status. Results: One hundred and fifteen HER2-positive/BRCA mutated cases were evaluated in comparison to the three control groups: HER2-positive/BRCA wild type (n = 129), HER2-negative/BRCA mutated (n = 222), HER2-negative/BRCA wild type (n = 234). HER2-positive breast cancers were more likely to have high histologic grade and high proliferation rate than HER2-negative neoplasms, regardless of BRCA mutation status. An interaction between BRCA mutations and HER2-positive status was found to correlate with worse survival after adjusting for prognostic variables (HR = 3.4; 95% CI: 1.3-16.7). Conclusions: Co-occurrence of BRCA mutations and HER2-positive status is a poor prognostic factor in patients with early or locally advanced breast cancer. This finding may be a proof of concept that a combined pharmacological intervention directed to these targets could be synergistic

Recurrent NF1 gene variants and their genotype/phenotype correlations in patients with Neurofibromatosis type I

Neurofibromatosis type I, a genetic condition due to pathogenic variants in the NF1 gene, is burdened by a high rate of complications, including neoplasms, which increase morbidity and mortality for the disease. We retrospectively re-evaluated the NF1 gene variants found in the period 2000\u20132019 and we studied for genotype/phenotype correlations of disease complications and neoplasms 34 variants, which were shared by at least two unrelated families (range 2\u201311) for a total 141 of probands and 21 relatives affected by Neurofibromatosis type I. Recurrent variants could be ascribed to the most common mutational mechanisms (C to T transition, microsatellite slippage, non-homologous recombination). In genotype/phenotype correlations, the variants p.Arg440*, p.Tyr489Cys, and p.Arg1947*, together with the gross gene deletions, displayed the highest rates of complications. When considering neoplasms, carriers of variants falling in the extradomain region at the 5\u2032 end of NF1 had a lower age-related cancer frequency than the rest of the gene sequence, showing a borderline significance (p = 0.045), which was not conserved after correction with covariates. We conclude that (1) hotspots in NF1 occur via different mutational mechanisms, (2) several variants are associated with high rates of complications and cancers, and (3) there is an initial evidence toward a lower cancer risk for carriers of variants in the 5\u2032 end of the NF1 gene although not significant at the multivariate analysis

The use of benzil to obtain functionalized N-heterocycles

In this work, the reactivity of benzil was studied, employing C, N- and N, N-nucleophiles, such as ethyl(3-amino substituted) 2-butenoates 4a-c , (S, Z)-ethyl 3-(1-ethoxy-3-hydroxy-1-oxopropan-2-ylamino)but-2-enoate 6, semicarbazide 8 or thiosemicarbazide 10, to evaluate their electrophilic centers as building blocks for the synthesis of the polyfunctionalized heterocyclic compounds, resulting in pyrrolinone 5a-c, pyrrole 7, triazinone 9 and triazinethione 11. The employed benzil 3 was obtained by the oxidation of the benzoin under solvent free conditions in a comparative study between different protocols of oxidation, using the methodology under mild reaction conditions and supported reagent associated to the microwave irradiation, with good results and without aggressive reagents

Estrategia de aula invertida con modalidad virtual. Estudio de caso en la formación de profesionales en ciencias naturales

A pocos días para el comienzo de las clases se presentó un fuerte cambio de contexto en el marco de la pandemia por SARS-CoV-2. Ante el crecimiento exponencial de contagios, el aislamiento social obligatorio fue una de las medidas principales adoptadas por los diferentes países del mundo. En esta realidad resultó inevitable retrasar o detener el dictado de clases en los distintos ámbitos académicos, especialmente de educación superior (Cayo-Rojas y Rosell, 2020). Como muchas instituciones educativas de Argentina, la UNC implementó el cursado completamente virtual de sus carreras. En la Facultad de Ciencias Agropecuarias, inmediatamente se comenzó a trabajar en la adaptación del dictado de todos los espacios curriculares hacia el Campus Académico.Como alternativa a las metodologías de enseñanza tradicionales surge el Aula Invertida como enfoque integral que fomenta el aprendizaje autónomo de los estudiantes, contando con acceso a los contenidos a través de entornos virtuales para luego aplicarlos en actividades diversas y participativas. En este trabajo se plantea valorar la implementación del modelo aula invertida para el dictado virtual del espacio curricular Fisicoquímica de la carrera Licenciatura en Agroalimentos de la Facultad de Ciencias Agropecuarias. Inicialmente, la asignatura fue planificada para llevarse a cabo mediante un enfoque de Aula Invertida, aprovechando los entornos virtuales desde un modelo de aprendizaje centrado en la construcción activa del conocimiento por parte de los estudiantes. Del total de alumnos matriculados, accedió a promoción directa de la asignatura el 62,3% y adquirió condición de alumno regular el 4,1%. Considerando que fue la primera vez que se dictó la materia, sin antecedentes de dictado presencial, se podría decir que los resultados fueron favorables ya que los alumnos demostraron en su gran mayoría una elevada adherencia a las actividades planteadas, a pesar de las vicisitudes presentadas por la dificultad de acceso a internet. Esta situación debe ser considerada al pensar la planificación de una asignatura desde la virtualidad.publishedVersionFil: Uliana, A. S. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Fundamentación Biológica. Cátedra de Biología Celular; ArgentinaFil: Prieto, María Cecilia. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Prieto, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Bergesse, A. E. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Bergesse, A. E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Camiletti, O. F. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina.Fil: Camiletti, O. F. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Mariani, E. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Fundamentación Biológica. Cátedra de Química Orgánica; Argentina.Fil: Valentinuzzi, M. C. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Ingeniería y Mecanización Rural. Cátedra de Física; Argentina

Intensity-duration-frequency of maximum rainfall in Mato Grosso State.

EN-US: Intensive rainfall is an important meteorological variable that is of technical interest in hydraulic projects. This study therefore generated Intensity-Duration-Frequency equations (IDF) for 14 weather stations in Mato Grosso State, based on pluviograph analysis. Annual maximum rainfall data regarding 10-to-1440-minute long rainfall events were collected from digitized daily pluviographs. Data adherence to the generalized extreme value distribution (GEV) was checked through the Kolmogorov-Smirnov test at a 20% significance level. Next, the maximum probable rainfall for return periods such as 2, 5, 10, 20, 30, 50 and 100 years was calculated and the IDF equations were adjusted. The performance of the IDF equations was evaluated based on mean absolute error (MAE), root mean square error (RMSE), bias, Willmott's concordance index and Nash-Sutcliffe efficiency index (ENS). Adjusting the IDF equations was only possible for rainfall durations ranging from 10 to 360 min at each station due to the low frequency of longer rainfalls. High variation was present in parameters of the IDF equation and in maximum rainfall intensity between stations. The satisfactory performance of the models, as attested to by statistical indices, allows using IDF equations adjusted for rainfall durations from 10 to 360 min, and return periods from 2 to 100 years, in the regions of the Mato Grosso weather stations. | PT-BR: A chuva intensa é uma importante variável meteorológica que apresenta interesse técnico em projetos hidráulicos. Assim, este estudo teve como objetivo obter equações intensidade-duração-frequência (IDF), obtidas por análise de pluviógrafos, para 14 estações no Estado do Mato Grosso. As séries anuais de intensidade máximas de chuva com duração de 10 a 1440 min foram obtidas de Pluviogramas diários digitalizados. Verificada a aderência das séries à distribuição generalizada de valores extremos, pelo teste de Kolmogorov-Smirnov à 20% de significância, calculou-se as chuvas máximas prováveis para os tempos de retorno de 2, 5, 10, 20, 30, 50 e 100 anos e, ajustaram-se as equações IDF. O desempenho das equações IDF foi avaliado pelo erro absoluto médio (MAE), erro quadrático médio (RMSE), bias, índice de concordância de Willmott e índice de eficiência de Nash-Sutcliffe (ENS). Em todas as estações foi possível ajustar apenas equações IDF para chuvas com duração de 10 a 360 min, devido à baixa frequência de chuvas com duração superior. Houve grande variação na intensidade máxima da chuva e dos parâmetros da equação IDF entre as estações estudadas. O bom desempenho dos modelos, conforme atestados por índices estatísticos, permitem a utilização das equações IDF para as durações de 10 a 360 min e tempo de retorno de 2 a 100 anos, nas regiões das estações do Mato Grosso

Infestação de plantas daninhas após diferentes coberturas invernais em espaçamentos e populações variados na cultura do milho.

O uso de técnicas integradas para o manejo de plantas daninhas torna-se uma ferramenta para adoção de manejo mais sustentável